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Washington University scientists explore the bottom of the world

This article first appeared in the St. Louis Beacon, April 16, 2009 - The concept of summer camp carries a different connotation for Washington University professor Douglas Wiens.

To be sure, Wiens slept in a bunk bed - a rickety one at that. And he spent his days exploring a mountain range, though with instruments instead of on foot. The temperatures were relatively balmy, too, if you consider 20 degrees below zero (Fahrenheit) comfortable.

Wiens spent an Antarctic summer at a field camp called AGAP South. It lies in East Antarctica a few hundred miles from the South Pole and about 2.5 miles above the ice-encased Gamburtsev Mountains.

Wiens, chair of earth and planetary sciences at Washington University in St. Louis, was among scientists from seven countries who coordinated efforts to study and map the mysterious Gamburtsev Mountain range lurking beneath the East Antarctic Ice Sheet.

The work, as part of the International Polar Year 2007-08, has unveiled the first detailed view of the last unexplored mountains on Earth. Scientists hope to shed light on the mystery of how and when the mountains formed as well as what role they may have played in the making of the ice sheet. Understanding the mountain-ice sheet relationship could guide climate models in predicting the effects of a warming planet, including rise in global sea levels.

Summer Camp in Snow and Ice

During the fleeting and frigid Antarctic "summer," when temperatures averaged in the negative 20 degree Fahrenheit range, two teams of scientists rushed to gather seismic and aerial survey data. They battled poor weather, extreme cold, high altitude, 24-hour sunlight and collapsing bunk-beds. "The bunk bed situation "was a hazard we were not anticipating," Wiens said.

Along with Wiens, the seismic team included three others from Washington University: Patrick Shore, a computer specialist in earth and planetary sciences, and David Heeszel and Amanda Lough, both graduate students in Wiens' lab. Researchers from Pennsylvania State University, the Incorporated Research Institutions for Seismology, and the Japan National Institute of Polar Research rounded out the seismic team.

Flying a Twin Otter aircraft to sites around East Antarctica, they set up a grid of 24 seismic stations and collected preliminary data from 10 other stations that ran over the previous winter. "We now have winter data from the middle of the continent, where we've never had winter data before," Lough said.

An Ultrasound for Mother Earth

To set up their stations, the scientists flew in a plane on skis that could land almost anywhere. "We'd have to land in the open field, which is always interesting," Lough said. "Some of the landings were really rough. You were worried you weren't going to get down. Other landings were really smooth, it was nice and soft, almost like sand," she said.

Once down, the team set to work burying the heavily insulated boxes containing the sensors and "brain" of the seismographs. Solar panels provide power in the summer and lithium batteries take over during the sunless winter, when temperatures average negative 100 degrees. But the instruments' own heat keeps them around minus 50.

Once installed, these seismographs measure seismic signals radiating from the mountains during earthquakes in other parts of the world (such as the powerful earthquake that struck China's Sichuan province last year). Like a planetary ultrasound, these signals can image what lies beneath the surface of the Earth, where the crust meets the mantel. Such information provides clues to what holds the mountains up. Wiens hopes preliminary data from the first 10 stations, still being analyzed, can help explain the mystery.

The same instruments can shed light on the ice itself. Lough's project is studying the movement of the Whillans Ice Stream, a massive river of ice that slides about 18 inches twice a day and empties into the Ross Ice Shelf. The "stick-slip" movement of the Whillans registers on the seismographs -- like a glacial-scale earthquake rumbling for 10 minutes rather than 10 seconds.

"It's a very strange and unusual pattern of motion," said Wiens, calling it important for understanding how ice moves in Antarctica, what controls its thickness, and how fast it might melt if the earth warms up.

The other scientific team, led by Robin Bell and Michael Studinger of Columbia University's Lamont-Doherty Earth Observatory, was dedicated to an aerial survey of the mountains. Flying another Twin Otter aircraft over the ice sheet's flat, white, almost featureless expanse (over an area about the size of Texas), they shot radar and laser through the ice and took magnetic and gravity measurements of the rock below. While the seismic data can image deep under Earth's surface, the aerial survey looks at the surface topography and composition of the mountains.

Antarctic 'Alps'

The Gamburtsev Mountains were first discovered in 1958 by a Soviet expedition to the Pole of Inaccessibility - so named because it is the point farthest from any of Antarctica's coasts. So inaccessible is this part of the continent that the mountains were almost totally unexplored until the current Antarctic Gamburtsev Province (AGAP) Project.

Scientists conducted a brief survey in the 1970s, but not until the AGAP project completed its field season in February could scientists "see" the vast under-ice landscape. It features shear peaks, deep valleys and a complex system of rivers and lakes - a landscape similar in size to the European Alps.

Unlike the Alps, however, scientists do not know how the Gamburtsev Mountains formed. According to the current understanding of East Antarctic geology, the Gamburtsevs have no earthly business being there. Indeed, finding mountains in the middle of a continent far from a tectonic plate boundary, with no known volcanic activity is "like opening the door of an Egyptian pyramid and finding an astronaut inside," according to a press release quoting Robin Bell.

Wiens also spoke of the mystery of the mountains. "According to what we might think, it doesn't make sense for a mountain range to be there. We think that the geology of that part of Antarctica would be very old, from before the age of dinosaurs. In general, regions that old don't have high mountain ranges," Wiens said. After hundreds of millions of years of erosion, one might expect to see a smooth plateau rather than jagged peaks and deep valleys.

"That they're seeing something relatively rugged suggests that there is a surprisingly young landscape under there," said John Goodge, professor of geological sciences at the University of Minnesota, Duluth, who also studies Antarctic geology, but was not involved in this project. Goodge points out, however, that they don't know yet how old it is as they are still wading through the massive amounts of data.

Making a Mountain Range

In general, mountains are held up in two ways, Goodge explained. One way is through dynamic lift. For example, hot mantel rising to Earth's surface can hold up mid-ocean ridges - the Indian sub-continent colliding with Asia holds up the Himalayas.

"Another way is to have a very deep root," Goodge said. To explain this concept, both Wiens and Goodge compared this type of mountain to an iceberg. Since the Earth's crust is lighter than the rest of Earth, you can think of it as floating on the Earth's mantel, Wiens explained.

Bigger icebergs, with more ice floating beneath the water, stick up higher above the surface. "It bobs up due to the buoyancy of the ice," said Wiens. The mountain we see is like the tip of the iceberg, explained Goodge.

Wiens is using the seismographs to look for warm spots in the mountains or a cold, thick crust. Warm spots suggest a younger mountain formed from dynamic lift. But a thick crust could suggest an older and colder mountain supported by a deep root.

The age of the mountain range and the age of the ice sheet are important. If the mountains were there before the ice sheet, scientists suspect the Gamburtsevs were the likely nucleation point for Earth's current ice sheets. If so, these mountains hold the world's oldest ice. Air trapped in that ice could provide samples of Earth's ancient atmosphere and help scientists better understand climate change.

Return to the White Continent

Field research in Antarctica is challenging work in a sometimes alien landscape. But these researchers go for the science and, perhaps, for the adventure. When installing many of the stations, Lough notes, "we were the first people ever to be at those locations." She hopes to go back next year.

While scientists sift through data, the mountains' mystery remains. Heading into the Antarctic winter, the instruments are now resting quietly beneath the snow, recording the world's earthquakes, probing the depths of the mountains far below, and awaiting the return of the scientists when the sun rises on the white continent once more.

Julia Evangelou Strait is a freelance science writer based in St. Louis. She has a master's degree in biomedical engineering and works in hospital epidemiology for BJC HealthCare.

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